Synthesis of SBA-Pr-CQC-BG as a heterogeneous ionic liquid and study of its sensor performance for Hg2+

The hybrid fluorescent chemosensor SBA-Pr-CQC-BG , as a heterogeneous ionic liquid, was created to combine the advantages of mesoporous silica and organic functional groups. To this end, SBA-15 was modified with (3-aminopropyl)triethoxysilane and then functionalized with 2-chloroquinoline-3-carbaldehyde to obtain SBA-Pr-CQC, which was reacted with benzoguanamine to obtain SBA-Pr-CQC-BG. Different analytical techniques were employed to characterize the synthesis of the ionic liquid. The tubular morphology was investigated using SEM, while the elemental composition was determined by EDX. The preservation of the crystalline structure was analyzed by low-angle XRD, and the reduction in the thermal stability was evaluated using TGA analysis. Also, fluorescence spectroscopy investigations of the heterogeneous ionic liquid in EtOH revealed its remarkable selectivity toward Hg 2+ ions, even in the presence of various cations, including Na + , Mg 2+ , Al 3+ , K + , Ca 2+ , Mn 2+ , Co 2+ , Cu 2+ , Zn 2+ , Cd 2+ , and Pb 2 + , with detection limit (LOD) of 1.4×10 – 5 mol L –1 . This work provides an effective strategy for improving the metal-ion selectivity of fluorescent sensors based on organic-inorganic hybrid mesoporous silica systems.